A. the temperature is accelerating.

B, add a proper amount of water and acid to dilute the retarder.

C, adding a small amount of CuSO4 to form an accelerated primary battery.

D. the amount of hydrochloric acid with higher concentration increases.

(2)

OH- has the same number of protons and electrons as 9 and 10.

A.HF 10 10

B.CH4 10 10

C.F- 9 10 (right)

D.Na+ 1 1 10

(3)

Selecting concentrated H2SO4 will passivate the iron can or aluminum can and form an oxide film on the surface, thus hindering the reaction.